The present invention relates generally to document processing or handling systems having a document feed magazine on which a stack of documents are supported in upstanding on-edge relation, and a document feeder assembly which finds particular application in feeding relatively thick heavy flat documents advanced from the feed magazine, and more particularly to an automatic magazine speed control for such a system which controls the speed at which documents are advanced to the feeder assembly.
Document handling or processing systems are known which include a document feed magazine on which documents, such as standard size mailing envelopes or larger size flats, are stacked in upstanding on-edge relation. The stacked documents are fed in sequential fashion to a feeder assembly operative to feed successive documents to an adjacent singulating station or the like from which the documents are fed one-at-a-time to a downstream processing station, such as a reader station having an optical character reader or bar code reader operative to read sort indicia on each document, such as an address or bar code, which determines a subsequent operation or sorting sequence. Other functions may be performed on the documents downstream from the singulating and reader stations. See, for example U.S. Pat. No. 4,955,956 which is incorporated herein by reference.
It is common in such document processing systems, such as post office sorting or commercial mass mailing establishments, for an operator to place stacks of aligned documents upon the feed magazine, which then advances the documents toward the feeder assembly. It is also common for gaps of varying length to exist on the feed magazine between documents and/or stacks of documents, these gaps resulting from interruptions in the operator's routine, operator fatigue, supply to the operator, and/or other variables. Since the feed magazine operates at a constant speed, there is a time delay, the length of which depending on the size of the gap, during which the feeder assembly is starved for documents.
In view of the fact that such document processing or sorting systems are designed with optimum rates of efficiency which are often critical to the commercial success of the system, the reduction of the number and length of such gaps in the feed magazine is a significant factor in the overall efficiency of the system.
Accordingly, it is an object of the present invention to provide an automatic speed control for a document processing system which minimizes or eliminates document gaps in the feed magazine.
It is another object of the present invention to provide an automatic speed control for a document processing system wherein the speed of the feed magazine is a factor of the number and concentration of documents being fed to the document feed assembly.
It is still another object of the present invention to provide an automatic speed control for a document processing system wherein upon the sensing of document gaps at the document feeder, the speed at which documents are advanced along the feed magazine is increased.
It is yet another object of the present invention to provide an automatic speed control for a document processing system wherein upon the sensing of a significant pressure exerted by a number of documents upon the feeder assembly, the advancement of documents by the feed magazine may be interrupted.